1. Field of the Invention
The present invention relates to a filtering apparatus of a circulating flush toilet, and more particularly, the present invention relates to a filtering apparatus of a circulating flush toilet, which effectively filters wastes in multiple stages contained in drain water having used for washing the inside of a toilet bowl.
2. Description of the Related Art
Hitherto, in a circulating flush toilet recycling drain water having used for washing the inside a toilet bowl, water having used for washing the inside of a toilet bowl is not discharged outside but is reused while being circulated in the toilet. As a result, the flush toilet has advantages in that an amount of consumed tap water can be reduced, and also a sewage installation can be eliminated. On the other hand, the flush toilet has a problem of foul water when its capacity of processing circulating water is decreased during operation or the number of frequencies of its usages increases. In order to solve such a problem, the inventor of the application has previously proposed a water-circulating apparatus of a flush toilet, which effectively purifies and circulates water used in the flush toilet so as to drastically decrease an amount of consumed tap water and also to lessen a burden of sewage processing (for example, see Japanese Unexamined Patent Application Publication No. 2002-339429, pages 2 and 3, and FIG. 1 (hereinafter, simply referred to as a patent document)).
The water-circulating apparatus of a flush toilet disclosed in the patent document includes a lower tank pooling drain water discharged from a toilet bowl; an aerating tank causing the drain water pumped from the lower tank to be aerated by a blower pump; a first separating tank pooling the drain water conveyed from the aerating tank and separating the drain water into clean water and sludge; an airlift pump discharging the sludge precipitated in the first separating tank into a sewage system; a second separating tank pooling the clean water conveyed from the upper part of the first separating tank and also separating it into clean water and sludge; and another airlift pump discharging the sludge in the second separating tank into the sewage system. With this structure, an amount of consumed tap water can be drastically reduced, a burden of sewage processing can be lessened, and also, an output of processed circulating water is increased, thereby contributing to an improved sanitary aspect.
However, in many circulating flush toilets including that disclosed in the above patent document, since a user often discards a sheet of commercially available tissue paper, a cigarette butt, and/or the like in a toilet bowl, such wastes are stored in the lower tank pooling drain water, and expand because of absorbing water, accordingly causing a problem of clogging of a pipe, a pump failure, or the like, and hence the wastes stored in the lower tank must be periodically removed.